JP2013112530A - Method for producing high-purity nickel sulfate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing high-purity nickel sulfate by removing efficiently magnesium from an inclusion, especially a precipitate, containing nickel.SOLUTION: This method for producing high-purity nickel sulfate includes a magnesium removal step of separating magnesium from a nickel inclusion by forming a mixture by bringing the nickel inclusion into contact with water, and then performing solid-liquid separation of the mixture.

Description

  The present invention relates to a process for efficiently removing magnesium from a precipitate containing nickel to produce high-purity nickel sulfate.

As a general method for industrially producing nickel sulfate, a nickel sulfate solution is obtained by dissolving a raw material in an acid solution, followed by a cleaning step for removing impurities, and further obtaining nickel sulfate crystals by evaporation crystallization, etc. There is.
Various methods are adopted for this liquid purification step depending on the impurities contained in the raw material. When cobalt is contained in the raw material, a solvent using phosphonic acid or phosphinic acid is an effective method for separating nickel and cobalt. Extraction methods are widely known.

As the phosphonic acid and phosphinic acid used in the solvent extraction method, 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester and di- (2,4,4-trimethylpentyl) phosphinic acid are excellent in extracting and separating nickel and cobalt. It is preferable.
Solvent extraction with these phosphonic acids and phosphinic acids depends on the pH of the solution, and the extraction rate improves as the pH increases. And the pH dependence with respect to extraction changes with elements, It is possible to extract cobalt and other impurity elements in an organic solvent using this characteristic.

  That is, the impurity element is distributed to the organic phase while the pH is set lower than the pH at which nickel is extracted, while nickel remains in the aqueous phase, so that a nickel solution from which impurities are removed can be obtained.

In addition, as shown in Patent Documents 1, 2, and 3, by extracting nickel into an organic solvent at a high pH in advance, by contacting the extracted organic solvent containing nickel with a nickel solution containing impurities, An exchange reaction occurs in which an element easily extracted from nickel moves to the organic phase, and nickel in the organic solvent moves to the aqueous phase, and impurities in the nickel solution can be removed.
This method is effective as a method for preventing impurity elements such as Na contained in the pH adjuster from being mixed into the nickel solution and contaminating the product.

  However, in the nickel sulfate cleaning process as described above, the reaction behavior of magnesium in the solution is similar to that of nickel, and it has been difficult to selectively remove magnesium from the nickel solution.

JP-A-10-310437 Japanese Patent Laid-Open No. 10-30135 JP 2004-307270 A

  An object of the present invention is to provide a method for producing high-purity nickel sulfate by efficiently removing magnesium from a nickel-containing material, in particular, a precipitate, in view of such problems of the prior art. .

  A first invention of the present invention that solves such a problem is a magnesium removal step of separating magnesium from a nickel-containing material by solid-liquid separation of the mixture after forming the mixture by contacting the nickel-containing material with water. It is a manufacturing method of the high purity nickel sulfate characterized by including.

  According to a second invention of the present invention, the nickel-containing material in the first invention is a precipitate containing nickel, and nickel and cobalt mixed sulfide, an industrial intermediate, crude nickel sulfate, nickel oxide, nickel hydroxide And a method for producing high-purity nickel sulfate, characterized in that it is any one of nickel carbonate.

  3rd invention of this invention is a manufacturing method of the high purity nickel sulfate characterized by including the grinding | pulverization process which reduces the magnesium quality contained by grind | pulverizing the nickel containing material in 1st and 2nd invention. is there.

  A fourth aspect of the present invention is a method for producing high-purity nickel sulfate, wherein the nickel-containing material in the first to third aspects has a particle size of 50 μm or less.

  According to the present invention, high-purity nickel sulfate having a low magnesium quality can be easily obtained, and the removal of magnesium from the nickel solution is low in cost because water is used, and the process is simple and has an advantage. .

It is a flowchart which shows an example of the manufacturing method of high purity nickel sulfate including the removal method of an impurity element. It is an application flow figure of Mg removal processing method in an example of a manufacturing method of high purity nickel sulfate of the present invention. It is a flowchart of the Mg removal processing method in this invention.

Below, the manufacturing method of the high purity nickel sulfate of this invention is demonstrated.
FIG. 1 is a flow chart showing an example of a method for producing high-purity nickel sulfate, and a high-purity nickel sulfate solution is usually produced from nickel-containing materials containing nickel by proceeding according to the white arrow 1. During the production process, the non-impurity element is removed from the nickel-containing material through the process of the “dashed line” frame and discharged out of the system as wastewater or wastewater starch. In the solution, the reaction behavior was similar to that of nickel, and the removal of magnesium from the solution containing nickel was insufficient.

Under such circumstances, the method for producing high-purity nickel sulfate according to the present invention comprises a nickel-containing material containing nickel produced and used during the production process of high-purity nickel sulfate as shown in the production process flow chart of FIG. After forming a mixture by contacting with water, solid-liquid separation is performed to separate the precipitate from the separated liquid, so that the Mg quality of the resulting precipitate is greater than the magnesium quality of the nickel-containing material before solid-liquid separation. It includes a reducing Mg removal treatment method (the process flow is shown in FIG. 3). In FIG. 2, the thick arrow indicates the “Mg removal treatment path”, the thin arrow indicates the “nickel sulfate production process path”, and the broken arrow indicates “the nickel sulfate solution without Mg removal treatment”. "Part of manufacturing process path".
The nickel-containing material used here is not particularly limited. Nickel and cobalt mixed sulfide formed by acid leaching and sulfidation of raw nickel oxide ore as a precipitate, and crude nickel sulfate as an industrial intermediate Nickel oxide, nickel hydroxide, nickel carbonate, etc. can be used.

As a method of obtaining a Ni-containing material dispersion mixture (aqueous solution) by bringing a nickel-containing material into contact with pure water, there is a repulp washing method in which the nickel-containing material is dispersed in pure water and stirred to elute magnesium element from the nickel-containing material. Although it is desirable, it is not particularly limited as long as it is a cleaning method capable of eluting magnesium element.
In addition, as shown in FIG. 3, it is possible to further reduce the magnesium quality in the nickel-containing material by performing physical grinding (pulverization treatment) before bringing the nickel-containing material into contact with water (pure water). It is.
An apparatus for performing physical pulverization is not particularly limited, and a general rod mill, ball mill, or the like can be used. When this nickel-containing material is pulverized, it is preferably pulverized to 50 μm or less.

  As the nickel-containing material for this pulverization treatment, the precipitate obtained by solid-liquid separation is more easily pulverized than the nickel oxide ore used as a raw material for nickel sulfate, in terms of the effect of removing magnesium. desirable.

  Hereinafter, the present invention will be described in more detail with reference to the drawings.

  According to the flow chart of FIG. 3, the nickel-cobalt mixed sulfide in the case of repulp washing in which the nickel-cobalt mixed sulfide having the particle size and magnesium grade shown in Table 1 as the nickel-containing material is brought into contact with water as shown in Table 1 The change in the magnesium quality was measured. The particle size was measured by the microtrack method.

Specifically, 100 g of nickel / cobalt mixed sulfide was collected and dispersed in 200 ml of pure water to form a mixture, and repulp washing was performed at room temperature for 15 minutes under stirring.
Then, it separated into solid and liquid, and analyzed the magnesium quality of the sulfide which is a deposit (Ni containing material), and the result is shown in Table 1. As an analysis method, ICP emission spectroscopic analysis was adopted.

  As shown in Table 1, it was confirmed that the magnesium quality of 50 ppm contained in the nickel / cobalt mixed sulfide was reduced to 30 ppm by washing.

  The nickel / cobalt mixed sulfide described in Table 1 used in Example 1 was pulverized and then washed with water, and the change in magnesium quality of the nickel / cobalt mixed sulfide was measured.

  Specifically, the nickel / cobalt mixed sulfide shown in Table 1 was pulverized, mixed with pure water, washed with repulp, and the change in magnesium quality was measured. Two types of grinding methods were used: a rod mill and a planetary ball mill.

[Rod mill grinding method]
A mixture was formed by dispersing 200 g of sulfide pulverized using a rod mill in 200 ml of pure water, and the pulp was washed under normal temperature for 15 minutes.

[Planet ball mill grinding method]
100 g of sulfide pulverized using a planetary ball mill was dispersed in 100 ml of pure water to form a mixture, and the pulp was washed under normal temperature for 30 minutes.
The particle size before and after pulverization was measured by the microtrack method.

  After washing, both were subjected to solid-liquid separation in the same manner as in Example 1, and the magnesium quality of the sulfide as a precipitate (Ni-containing material) was analyzed. The results are shown in Table 1. As an analysis method, ICP emission spectroscopic analysis was adopted.

From Table 1, when pulverized with a rod mill, the particle size indicated by D90 was pulverized from 103 μm to 48 μm before washing, and the magnesium quality was reduced from 50 ppm to 20 ppm.
On the other hand, when pulverized using a planetary ball mill, the particle size indicated by D90 was refined to about 3 μm, but the magnesium quality was the same as in the rod mill pulverization.
As can be seen from the above, excessive pulverization increases the cost required for pulverization. In addition, there is an unfavorable influence such that the sulfide is easily oxidized and dust generation is promoted or there is a possibility of ignition.
Therefore, it can be seen that the mixed sulfide can be sufficiently pulverized to have a particle size indicated by D90 and pulverized to a level of 50 μm or less.

  Using the sulfides obtained in Examples 1 and 2 as raw materials, a high-purity nickel sulfate solution was prepared according to the flow chart of FIG. The magnesium quality at that time was measured by the same method as in Example 1. The results are shown in Table 2.

(Comparative Example 1)
Table 2 shows the magnesium quality when nickel sulfate was produced in the leaching process indicated by the broken line arrow in FIG. 2 and the remelting process for the mixed sulfide without using the Mg removal treatment method. Show.

  As is apparent from Table 2, in Example 3 where the Mg removal treatment was performed, a nickel sulfate solution having a sufficiently low magnesium quality was obtained compared to Comparative Example 1 where the Mg removal treatment was not performed. Recognize.

Claims (4)

  A method for producing high-purity nickel sulfate, comprising: removing a magnesium from the nickel-containing material by bringing the nickel-containing material into contact with water to form a mixture, followed by solid-liquid separation of the mixture. .   The nickel-containing material is a precipitate containing nickel, and is one of nickel and cobalt mixed sulfide, industrial intermediate crude nickel sulfate, nickel oxide, nickel hydroxide, and nickel carbonate. The manufacturing method of the high purity nickel sulfate of Claim 1.   The method for producing high-purity nickel sulfate according to claim 1, further comprising a pulverizing step of reducing the magnesium quality contained by pulverizing the nickel-containing material.   4. The method for producing high-purity nickel sulfate according to claim 1, wherein a particle diameter of the nickel-containing material is 50 μm or less.

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